main and return question

Just a quicky.

I'm a newcomer to C and obviously want to pick up as few bad habits as I can. One thing that I would like some input on is the correct use of "main()" and "return".

Some texts I am using code main as:

Code:

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main()

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while others show:

Code:

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int main()

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the same confusion I have is with return:

Code:

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return 0;

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or

Code:

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return (0);

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which is correct or does it not matter?

Cheers all :)

it doesnt matter it will return 0 in the end

Quote:

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Originally Posted by lolguy

it doesnt matter it will return 0 in the end

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Well, as long as there IS a return 0 at the end, yes.

Code:

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return (0);

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is identical to

Code:

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return 0;

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or indeed:

Code:

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return (((((((0)))))));

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The forms of:

Code:

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main()

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(called implicit return type) and

Code:

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int main()

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(explicit return type) are also identical, except the former is only valid in the older C89 standard - the newer C99 standard means that "implicit return type" is no longer valid.

It is highly recommended to use the modern version when writing new code, but it is also good to be aware that old-style code is out and is valid in existing C89 compilers (most compilers have an option to support C89 style code, if that's not the default).

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Mats

http://faq.cprogramming.com/cgi-bin/...&id=1043284376

Quote:

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Originally Posted by matsp

Well, as long as there IS a return 0 at the end, yes.

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Though in C99, 0 will be returned if control reaches the end of the main function without encountering a return statement.

Thanks for the responses all.

Confusion cleared.

Quote:

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Originally Posted by laserlight

Though in C99, 0 will be returned if control reaches the end of the main function without encountering a return statement.

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^^ arrgh! My brains! :D

Quote:

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Originally Posted by BuzzBuzz

^^ arrgh! My brains! :D

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Yes, it's hard to decide what is relevant information and to whom, especially if nobody else knows either.

In this context, just consider the difference between something that is okay somewhere, and something that is okay everywhere.

Quote:

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Originally Posted by BuzzBuzz

^^ arrgh! My brains! :D

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If you ALWAYS have a return 0, you never need to remember whether it is needed or not - it is NEVER WRONG to end main with a return 0 - it CAN be right or wrong to NOT do so.

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Mats

Unless it's unreachable code - some function calls "exit(n)" legitimately. Compiler may yell at you. Oh well.

Quote:

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Originally Posted by nonoob

Unless it's unreachable code - some function calls "exit(n)" legitimately. Compiler may yell at you. Oh well.

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Yeah, obviously there are cases where you never leave main with a return, in which case putting a return 0 will have no negative or positive effect on the code at all. A good quality optimizer in the compiler will remove unreachable code. If you have a poor quality optimizer in the compiler, it may not remove unreachable code - but it's almost certainly a bigger problem with other functions than main.

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Mats